The invention relates to a cover, in particular for an explosion-proof luminaire. Luminaires of this nature generally comprise a housing and at least one light source, whereby a housing opening is closed by a cover of this nature. The cover generally comprises a mounting frame, which is detachable from the luminaire, and a transparent luminaire cover held at least along a circumferential edge by the mounting frame. Light from the light source emerges from the luminaire cover to facilitate appropriate illumination. Explosion-proof luminaires of this nature can be floodlight reflecting luminaires, searchlight luminaires, pendant luminaires or also other luminaires. An appropriate light source is, for example, a halogen bulb, filament bulb, high-pressure discharge tube or a plurality of light emitting diodes (LEDs). Apart from the appropriate light source, associated electrical and electronic equipment can be included for the operation and control of the light source in the explosion-proof luminaire.
A luminaire of this nature is employed in various temperature ranges. With both normal operation of the luminaires or also during tests or the like there is the danger that microcracks occur in the luminaire cover. They can negatively affect the stability of the luminaire cover and in particular the explosion-proof properties.
In order, for example, to avoid microcracks due to the effect of impacts, luminaires are presently being used in which the transparent luminaire cover is protected by a grid-like metal structure. However, such grid structures cannot be used for all luminaires, because, amongst other things, a large number of unwanted shadows can be produced by the grid structure.
In practice a further luminaire is known in which the transparent luminaire cover is relatively thick to avoid microcracks of this nature.
Both above mentioned examples lead to increased costs and increased weight. In addition, generally the light output is negatively affected; refer, for example, to the above mentioned shadows.